R53 JCW Misfire
Discussion
Hey guys. Trying to fault find a misfire problem and wanted some advice on potential replacement parts options. I'll copy bits of a thread from Mini2 so if it looks a bit odd that's why 
Jamesk said:
The car has FBMWSH culminating in an inspection 2 about 1750 miles ago before I bought the car. It has done 54,000 miles and is in great shape in all other respects.
I have noticed a misfire when the car is under load (say 50% throttle or more) in the higher gears. It only happens at low revs and seems to be more prominent the higher the gear. It doesn't do it in 1st and very very rarely in 2nd but in all other gears I can reproduce the misfire more or less at will between 2500 and 3500 rpm. Above that rpm no problem in any gear. Car pulls hard and I don't doubt it's using all the horses BMW gave her!
There are no warning lights.
No leaks (air or fluid) that I can see.
Have poked the leads etc - nothing obviously lose.
Its not the ECU 1st gear thing that I read about.
So, potential problem areas?
Spark plugs (shouldn't be as just replaced?)
Ignition Leads?
Bypass Valve?
Coil Packs?
Some random air hose?
Injectors?
I'm thinking of replacing the coil pack first as the dealer I spoke to had come across these breaking down before. Then probably leads. Does anyone know what parts I need for the JCW? Are their aftermarket options?I have noticed a misfire when the car is under load (say 50% throttle or more) in the higher gears. It only happens at low revs and seems to be more prominent the higher the gear. It doesn't do it in 1st and very very rarely in 2nd but in all other gears I can reproduce the misfire more or less at will between 2500 and 3500 rpm. Above that rpm no problem in any gear. Car pulls hard and I don't doubt it's using all the horses BMW gave her!
There are no warning lights.
No leaks (air or fluid) that I can see.
Have poked the leads etc - nothing obviously lose.
Its not the ECU 1st gear thing that I read about.
So, potential problem areas?
Spark plugs (shouldn't be as just replaced?)
Ignition Leads?
Bypass Valve?
Coil Packs?
Some random air hose?
Injectors?
Thx for the replies
The fuel "should" be the good stuff but it wqs full when I bought it so haven't put any of mine in yet. Will make sure its the highest octane I can find.
Funnily enough the servicing dealer did put coil pack at the top of his list too, but I guess he would say that given he just did the plugs! Does anyone have the part number handy?
The fuel "should" be the good stuff but it wqs full when I bought it so haven't put any of mine in yet. Will make sure its the highest octane I can find.
Funnily enough the servicing dealer did put coil pack at the top of his list too, but I guess he would say that given he just did the plugs! Does anyone have the part number handy?
Was it happening before the plugs were done?
If not I would say leads may have been put back in the wrong order, although if they are right don't rule out the plugs, may be faulty from new.
Rather than throwing money at it for bits find your local specialist and get them to have a look and diagnose.
If not I would say leads may have been put back in the wrong order, although if they are right don't rule out the plugs, may be faulty from new.
Rather than throwing money at it for bits find your local specialist and get them to have a look and diagnose.
JamesK said:
I didn't have the car before plugs were changed. I appreciate the sentiment but paying a speacialist to diagnose may end up costing me more than replacing the most likely parts...
Is there a trusted indy in Essex area?
1320 mini or lohen, not sure how local though depending where you are in Essex, even then may be a bit of a drive.Is there a trusted indy in Essex area?
Easiest thing to check then is that plugs are the right ones and that the ignition leads are in the right order, fresh fuel wouldn't do any harm either. It may work out cheap to buy new parts if you guess right on the parts and change the right bit early on, but if you dont it will soon get past the diagnostic charge of a specialist, especially if you then sourced and fitted the part yourself.
Eta mini2 is pretty much dead, would suggest totalmini or minitorque if you are using mini forums
Edited by Brite spark on Monday 2nd January 00:05
Hmm well those 2 are far too far away sadly.
Need the appropriate socket before I can physically inspect plugs but leads all seem ok and in the right places. No corrosion on coil pack connectors etc. new fuel in and no difference thus far.
Is there a way of retrieving fault codes or do I need a specialist reader? Really don't want to dump it at a stealers...
Need the appropriate socket before I can physically inspect plugs but leads all seem ok and in the right places. No corrosion on coil pack connectors etc. new fuel in and no difference thus far.
Is there a way of retrieving fault codes or do I need a specialist reader? Really don't want to dump it at a stealers...
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